12-05-2007 Celestial Harvest (Article 85)

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Simon Kenny
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Location: Shannon, Co. Clare, Ireland

12-05-2007 Celestial Harvest (Article 85)

Post by Simon Kenny » Wed Feb 04, 2009 10:57 am

Celestial Harvest (Article 85)

Our terrestrial image of a harvest tends to be associated with a particular season, whereas in the night sky there is a celestial harvest every season. One of spring’s finest symbolic offerings is a cluster of stars in the faint constellation Cancer, known as Praesepe (Latin for manger), or the Beehive Cluster. Catalogued as M44, this open cluster lies only 577 light years from Earth, and is easily visible to the unaided eye as a dim glow. Should it not be readily observable, follow an imaginary line from Pollux in Gemini to Regulus in Leo. M44 lies just under half way along the path out from Pollux. This sprawling commune shines with the combined light of its more than 350 stellar members, and is very obvious on a clear night. Canadian explorer Thomas James, while seeking the famous Northwest Passage, penned his casual observation at nightfall on 31st January, 1632: “I could see the Cloud in Cancer full of small Starres”.

With the slightest optical aid, it seems to come alive in dazzling character, with up to 30 stars being visible in binoculars. A definite wow object, Praesepe is a must see during this time of year. Many of the stars in this astronomical gem form interesting pairs, or patterns looking like a ghostly sheen of cobwebs. In a small telescope, up to fifty can be seen, including a few reddish and orange tinted stars, which add colourful contrast to the slightly bluish sheen many of the others. Best views are however with binoculars or the finderscope of your telescope, as its apparent size is 1.5 degrees wide, or three full moon widths.

The Beehive Cluster is estimated to be over 400 million years old, thus still an infant compared to our Sun at 4.5 billion years! Known as the “weather forecaster” of the ancients, the first recorded entry of this object was by Aratos in 260BC, where he called it a “little mist”, while its true physical nature awaited Galileo’s observations with his crude telescope in 1610.

With the Dept. of Physics in UL (our co-hosts and sponsors) Shannonside Astronomy Club are very proud to present a talk by the world renowned Prof. David Malin called “Capturing ancient light”. David has been involved with scientific imaging for 45 years, initially as a microscopist and later as photographic scientist and astronomer with the Anglo-Australian Observatory. His pictures have been made into a series of exhibitions that have toured all the major countries. He has worked with Australian composers Martin Wesley-Smith and Ross Edwards on audio-visual productions, which combine astronomical images with modern music. His talk is at 7:30pm on 15th May in Room FB 028 in the Foundation Building (The University Concert Hall) — entry only through the doors of the Foundation Building (on the fountain side). Admission is free and open to members of the public. Details on our web site.

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